Surface Plasmon Resonance (SPR) may be used to investigate the binding characteristics of chemical and/or biochemical entities such as molecules or biomolecules found (or potentially found) in an analyte to a microarray of test patches. It may be desirable to expose the microarray to a series of analytes, buffers, washes, etc. to perform one or more tests using a flow cell. In some embodiments, it may be necessary to provide flow to an SPR flow cell for several hours or more, such as to accurately determine low value kinetic constants, to perform a series of tests over a period of time, etc.
Since SPR effectively measures local indices of refraction at the test patches on the microarray surface, and changes in fluid pressure or flow may affect the index of refraction, it may be desirable to minimize variations in fluid pressure within the test cell. It may also be desirable to minimize periods of non-flow through the flow cell, such as to maximize throughput, preserve concentration gradients near test patches, maintain fluid temperature, maximize reactivity of the test patches, allow for complex test protocols, collect data for accurate determination of kinetic constants, and/or provide other benefits.